Tube still and furnace construction



I Jan. 21, 1936. I I J. 5. WALLIS ETI'AL 2,023,305

TU BE STILL AND FURNACE CONSTRUCTION Filed 'Aug 51, 1931 2 Sheets-Sheet1 ATTORN Jan. 21, 1936. J. 5 w 's AL I 2,028,305

TUBE STILL AND FURNACE CONSTRUCTION Filed Aug. 31, 1931 2 Sheets-Sheet 2R5 Job/7 5. V/a/Ms Patented Jan. 21, 1936 UNITED' STATES PATENT OFFICETUBE STILL AND FURNACE CONSTRUCTION John S. Wallis and Stephen' B. deBenceyNew York, N. Y., assignors to Al co Products, Incorporated, NewYork, N. Y., a corporation of. Delaware Application August 31, 1931,Serial No. 560,438

2 Claims.

of radiant heat, the violent heating of the oil inthis bank results inits decomposition and a deposit of carbon. This is particularly true ofthe upper tubes in the convection bank. It has been found that atemperature of 1400 F. should not be exceeded for the entrant gases intothe convection bank.

This necessitates the reduction of the furnace temperature by an excessof air with its consequent loss in efficiency or of the use of a heatabsorbing means above the convection bank as described in United StatesLetters Patent to Primrose, 1,568,182.

In the Primrose patent it was pointed out that the radiation of heatfrom'that portion of the roof directly over the convection bank raisedthe temperature of the top rows of the convection bank to such an extentthat carbon deposition took place in these tubes, necessitating frequentshut-downs. Primrose solved the problem by the use of heat absorbingelements positioned over the convection bank so that the radiation ofheat was cut down due to the fact that it was absorbed. The presentinvention is directed to another mode of solving the problem.

Then, too, in existing types, the products of combustion sweep the rooftubes resulting in the heating of the roof tubes by convection gasescontrary to the intention of the design. Furthermore, a considerableturbulence of the convection gases takes place in the dead corner of thefurnace or still existing over the convection bank.

One object of our invention is to increase the efficiency of a tubestill by eliminating the necessity for the use of an excess of air or ofthe employment of an absorbing means and yet prevent the overheating ofthe convection bank.

Another object of our invention is to provide means for substantiallyreducing the turbulence of the convection gases.

A further object of our invention is to reduce the contacting of theproducts of combustion with the roof tubes.

Further objects will appear from the detailed description of ourinvention appearing below.

Fig. 1 shows a section of a vacuum still embodying my invention.

Fig. 2 is a section of an atmospheric pipe still equipped with myinvention.

In general, our invention contemplates increasing the dimension from thetop of the bridge Wall to the lowest row of roof tubes. We provide aconstruction oi. the tile over the convection bank which will give astream line flow of the gasesv entering it. By inclining: the wall ofthe still, above the convection bank, at a suitable angle, we areenabled not only to substantially reduce turbulence of the convectiongases, but also to reflect the radiant heat back into the firing chamberand away from the top row of the convection tube bank. By placing theconvection bank somewhat rearwardly of its usual position, we areenabled to incline the entrant passage of the gases leading into theconvection bank and thus obtain a flatter line of flow of the gases fromthe furnace preventing their flowing up through the roof tubes.

More particularly referring now to the drawings, Fig. 1 shows a sectionof a vacuum still embodying our invention, having roof tubes I and 2.The upper tubes 2 are of larger diameter than the lower tubes I topermit the vacuum to reach a point in the tubes below which thetemperatures are sufiiciently high to bring about a crackingdecomposition. This is described in United States Letters Patent toHarnsberger, 1,666,597, and forms no part of our invention.

A bridge wall 3 protects the convection bank tubes 4 from the radiantheat of the furnace chamber 5. Suitable oil burners 6 are provided. Itis to be understood, however, that while we have shown an oil firedfurnace, pulverized or other fuels may be used. It is to be noted thatthe convection bank is spaced rearwardly. The inclined wall 1 is placedat an angle such that the radiant heat from the furnace chamber 5 isreflected away from the convection tubes 4 and into the furnace chamber.The converging passage 8 formed by the inclined wall 1 and the inclinedtop 9 of the bridge wall substantially reduces the turbulence of thegases entering the convection bank and provides a stream line flow. Thegases pass down through the convection bank and out through flueconnection In, Petroleum oil enters at H and flows up through theconvection tubes, thence through the roof tubes to oil outlet I2. I 3and I 4 are the conventional inlet and outlet from the steamsuperheater.

In the vacuum still, the flow is two to carry the convection tubes.

throughout. By two to carry we mean that the flow of the oil through thetube still is through a pair of tubes in parallel throughout thefurnace.

Fig. 2 represents an atmospheric tube still embodying our invention.Like reference numerals indicate like parts. It is to be noted that theroof tubes l and 2 in the atmospheric still are of the same size. Thecirculation in the atmospheric still is four to carry in the convectionbank and two to carry in the roof bank. The action of the inclined wall1, the bridge wall 3 and the converging passageway 8 is the same in theatmospheric still as it is in the tube still.

It will be appreciated that our Construction gives a stream line flow ofthe gases entering the convection bank. Turbulence of the convectiongases is substantially reduced. The products of combustion areprohibited from coming in contact with the roof tubes. The tile over theconvection bank reflects the heat of radiation back into the furnace,rather than on the top row of It will be seen that we haveaccomplishedthe objects of our invention.

It will be understood that certain features, and sub-combinations are ofutility and may be employed without reference to other features andsub-combinations. This is contemplated by and is within the scope of theappended claims. It is further obvious that various changes may be madein details, within the scope of the claims appearing below withoutdeparting from the spirit of our invention and it is, therefore, to beun-- derstood that our invention is not to be limited to the specificdetails shown and described.

Having thus described our invention, what we claim is:--

I. In a tube still of the character described having a boundary wallhaving a bare interior surface downwardly inclined to the horizontal, afire chamber, a roof tube bank adapted to be 10 heated mainly by radiantheat, a tube bank adapted to be heated mainly by convection heat,abridge wall interposed between the fire chamber and said last mentionedtube bank said bridge wall having an inclined portion spacedlypositioned from 16 said inclined boundary wall and adapted to form adownwardly converging passageway therewith leading from said firechamber to said tube bank adapted to absorb convection heat.

2. In a tube 'still having a boundary wall hav- 20 ing an inclinedportion, a fire chamber having a horizontal roof, a bridge wall, a tubebank positioned between said boundary wall and said bridge wall andhaving a portion thereof spaced free of the vertical projection of saidroof, said bridge wall having an inclined portion defining with theinclined portion of said boundry wall an inclined passageway leading tosaid tube bank from said fire chamber.

JOHN S. WALLIS. STEPHEN B. m: BENCE.

